A Light and Effective Wide Field Monitor for Gamma Ray Bursts and Transient Sources

We present here a concept for a light and low-power wide field monitor working in the X-ray range, suitable for simultaneous imaging of large portions of the sky and GRB localizations. Our concept evolves from and improves on the design of the 5-kg SuperAGILE experiment, flying on the AGILE mission and currently delivering arcmin-localizations of GRBs at a rate of about 1/month. Similar to SuperAGILE, our concept is based on position sensitive silicon detectors equipped with one-dimensional coded masks. Different options are available for the detector, whose properties, combined with the scientific requirements, drive the design of the experiment. Our approach is based on a modular detector. The experiment design can then be tailored to specific scientific goals of the experiment or the mission (e.g., to cite GRBs only: the brightest GRBs/XRFs on a large field of view-FoV, or many low-fluence GRBs/XRFs on a smaller FoV, or the low energy spectrum of the prompt event, or the detection of high-z GRBs). In this paper we describe the concept, the main detector properties and outline some possible experiment configurations, with examples of their expected performance. Different experiment configurations in terms of area, FoV, angular resolution may be designed starting from the same detectors. Instead, the band-pass is mostly related to the detector properties. A key point of our project is the high degree of readiness of the detectors that are at production level and may be immediately proposed for a future experiment onboard missions with high readiness requirements.